Back stretching machines have been introduced to help a person stretch their back, typically focused on the lower back, to alleviate pain and provide therapy. As understood herein, many such machines suffer from the drawback of imposing a one-size-fits-all stretching regime on users. For example, inclined or vertical boards on which a person hangs to allow gravity to pull the upper body down away from the elevated lower back places the entire weight of the upper body at the stretching point, and moreover can deleteriously cause higher blood pressure in the person's head. Moreover, a person typically must accept that the stretching force is imposed straight along the spine, when a person's particular back malady may be better treated by allowing the person to establish the force off-axis from the spine and to vary both the magnitude and direction of the stretching force.